1. Technical Field
This invention relates to the field of teleconferencing, and more specifically to a method and apparatus that promote eye contact between participants in a video teleconference.
2. Description of the Prior Art
Face-to-face conversation is universally recognized as the preferred form of human contact. In business, this preference for direct human contact is manifest through person-to-person conversations and meetings where a plurality of persons participate in the exchange of information. So fundamental is the need to communicate directly, that even when people are geographically dispersed, meetings are arranged to bring people from different cities together to communicate ideas and debate issues.
It is well known that bringing people together can be an expensive proposition. Even when people work only a few hundred feet from each other, as for instance on different floors of an office building, time is wasted by walking to the other person""s office. When the distances are more extreme, people incur travel expenses and waste time in transit just so that they can talk to each other directly. The almost primal need to communicate face-to-face provides the rational basis for incurring the overhead expenses inherent in getting parties together for the purposes of direct communication.
Almost from the dawn of recorded history, there have been efforts to abridge the distances between people who want to speak to each other. Signal drums in the jungle and smoke signals used by native Americans are just two examples of such efforts. Modernly, effective methods for allowing people to communicate across distances began with the telephone. Using the telephone, people could talk to each other in a natural fashion. The only thing that was missing is that two people talking over a telephone could not see each other.
The visual element of communication is extremely important. In business communications, body language can convey subconscious messages from one person to the other. Many people learn how to read and rely on these signals in order to qualify the verbal content of the conversation. Imagine what poker would be like if the visual tell-tales were eliminated from the game. This is why extensive resources have been dedicated to the development of video teleconferencing systems. By adding a video capability to a telephone call, otherwise tacit information could again be perceived.
In a typical video teleconferencing system, each participant faces a video display device. The system also includes a microphone, a speaker, and a video camera. The video camera is normally positioned immediately above the video display and is pointed toward the local conversation participant. Using video teleconferencing, people speaking to each other could again read body language as one way of ascertaining the unspoken messages behind a conversation.
Body language is a strong signaling means and many people have learned to interpret the underlying unspoken messages. Unfortunately, many aspects of reading body language rely on eye contact between the two people engaged in conversation. Because the bore-sight of the camera is not coincident with the participant""s view-sight of the video display, known video teleconferencing systems can not convey eye contact between the people engaged in conversation. Consequently, many of the body language messages that involve eye contact can not be interpreted by either side.
One prior art solution to the eye contact problem was to use a beam-splitter to allow the user to view a reflected image of the video display while a video camera captures a head-on view of the user through the beam-splitter. A physical limitation in this prior art technique required positioning the beam-splitter at a 45xc2x0 angle to the surface of the video display. If the angle were any less than 45xc2x0, the image on the display screen would show up in the image captured by the camera. Because of the large minimum angle of 45xc2x0, implementations of the prior art were very bulky and awkward.
The invention comprises a method and apparatus for conveying eye contact from one video teleconferencing participant to another. According to the method, a video signal is received from a remote location and comprises an image of a remote participant. This signal is then presented onto a video display. The method further calls for the placement of a beam-splitter in front of the video display. The beam-splitter is canted away from the surface of the video display at an angle less than 45xc2x0.
A local participant is positioned in front of the video display and his image, as reflected by the beam-splitter, is captured by a video camera. The reflected image of the local user, as captured by the video camera, appears superimposed on a portion of the remote image displayed on the video screen. The remote video signal is clipped and morphed to account for the field of view of the video camera and the oblique perspective view of the video display perceived by the video camera. The processed rendition of the remote signal corresponds to the background captured by the video camera and this background signal is electronically removed from the image captured by the video camera. The resultant signal contains only the reflected image of the local participant.
In one alternative embodiment, the method calls for capturing the reflected image of the local participant directly from the surface of the video display. In this alternative, a beam-splitter is not required, but the local user is disposed with and in angular displacement from the normal of the video display surface.
In all embodiments, a plurality of targets may be inserted into the video signal received from the remote location. These targets facilitate the coincident subtraction of the background image from the image captured by the camera leaving only the reflected image of the local user represented in the resultant video signal.